Chloro(triphenylphosphine)gold(I) or triphenylphosphinegold(I) chloride is a
coordination complex
A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as '' ligands'' or complexing agents. M ...
with the formula (
Ph3P)AuCl. This colorless solid is a common reagent for research on gold compounds.
Preparation and structure
The complex is prepared by reducing
chloroauric acid
Chloroauric acid is an inorganic compound with the chemical formula . It forms hydrates . Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar anion. Often chloroauric acid is handled as a soluti ...
with
triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists ...
in 95%
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
:
:HAuCl
4 + H
2O + 2 PPh
3 → (Ph
3P)AuCl + Ph
3PO + 3 HCl
Ph
3PAuCl can also be prepared by treating a thioether complex of gold like (dimethyl sulfide)gold(I) chloride,
Me2S)AuCl with triphenylphosphine.
The complex adopts a linear coordination geometry, which is typical of most gold(I) compounds.
It crystallizes in the orthorhombic space group ''P''2
12
12
1 with a = 12.300(4) Å, b = 13.084(4) Å, c = 10.170(3) Å with Z = 4 formula units per unit cell.
Reactivity
Triphenylphosphinegold(I) chloride is a popular stable precursor for a cationic gold(I) catalyst used in organic synthesis.
Typically, it is treated with silver(I) salts of weakly coordinating anions (e.g., X
– = SbF
6–, BF
4–, TfO
–, or Tf
2N
–) to generate a weakly bound Ph
3PAu–X complex, in equilibrium with the catalytically-active species
h3PAusup>+X
– in solution. Among these, only the
bistriflimide
Bistriflimide, also known variously as bis(trifluoromethane)sulfonimide, bis(trifluoromethanesulfonyl)amide, bis(trifluoromethanesulfonyl)imidate (and variations thereof), informally and somewhat inaccurately as triflimide or triflimidate'','' or ...
complex Ph
3PAuNTf
2 can be isolated as the pure compound. The
nitrate
Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insolu ...
complex Ph
3PAuONO
2 and the
oxonium species
Ph3PAu)3Osup>+
F4sup>– are also prepared from the chloride.
As shown in the scheme below, the methyl complex Ph
3PAuMe is prepared from triphenylphosphinegold(I) chloride by transmetalation with a Grignard reagent. Further treatment of Ph
3PAuMe with methyllithium displaces the phosphine ligand and generates lithium di- and tetramethylaurate, Li
+ uMe2sup>– and Li
+ uMe4sup>–, respectively.
References
{{Gold compounds
Triphenylphosphine complexes
Gold(I) compounds
Chlorides
Chloro complexes
Gold–halogen compounds